(1) Field of the Invention
The present disclosure relates to a composite resin molded article and, more particularly, to a composite resin molded article excellent in especially the mechanical properties.
(2) Description of the Related Art
What-is-called “general-purpose plastics” such as polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC) each not only is very inexpensive but also is easily used for molding and is lightweight to have a weight of one several-th of the weight of a metal or a ceramic in a comparison therebetween. The general-purpose plastics are therefore each often used as a material of a variety of livingware such as a bag, various packages, various containers, and sheets and as a material of industrial parts such as automobile parts and electric parts, daily-use articles, and general merchandizes.
The general-purpose plastics however each have disadvantages such as insufficient mechanical properties. The current situation is therefore that the general-purpose plastics each do not have sufficient properties that are required to the materials used in various industrial products including mechanical products such as automobiles, and electric, electronic, and information-related products and the range of their application is limited.
On the other hand, what-is-called “engineering plastics” such as polycarbonates, fluorine resins, acrylic resins, and polyamides are each excellent in the mechanical properties and are used in various industrial products including mechanical products such as automobiles, and electric, electronic, and information-related products. Engineering plastics are however each expensive, and each arise a problem that recycling of monomers thereof is difficult and a load thereby on the environment is heavy.
It is therefore demanded to significantly improve the material properties of each of the general-purpose plastics (such as the mechanical strength). A technique is known according to which the mechanical strength of a general-purpose plastic is improved by dispersing a natural fiber, a glass fiber, a carbon fiber, or the like to be a fibrous filler in the resin of the general-purpose plastic for strengthening the general-purpose plastic. Above all, organic fibrous fillers such as cellulose are inexpensive and are also excellent in the environment-friendliness at the time of their disposal, and therefore each attract attention as a strengthening fiber (see, e.g., Japanese Patent Publication No. 5577176).
Each company is advancing studies to improve the mechanical strength of each of the general-purpose plastics and, in the '176 publication, the elastic modulus is increased and the dimensional stability is improved by adding a cellulose fiber whose maximal fiber diameter is 100 nm or smaller and whose aspect ratio is 2,000 or larger.